General-Purpose Fuse Bits

The AT32UC3 have 32 general-purpose fuse bits. When these bits are erased, they are at 1.

 

The wizard allow user to change few bit: ISP_BOD_EN, ISP_IO_COND_EN and ISP_FORCE.

 

General-Purpose Fuse Number

Name

Description

15:0

LOCK

Flash region lock bits. There is one bit per flash region. A value of 1 means the region is unlocked.

16

EPFL

EPFL External privileged fetch lock. It is used to prevent the CPU from fetching instructions from external memories when in privileged mode. A value of 1 means the external privileged fetch is unlocked.

19:17

BOOTPROT

Used to set the size of the bootloader protected area.

25:20

BODLEVEL

Brown-out detector trigger level. The higher the value, the higher the BOD threshold level.

26

BODHYST

Enables the BOD hysteresis when at 1.

28:27

BODEN

Hardware BOD enable state.

29

ISP_BOD_EN

Tells the ISP to enable by software the BOD when at 1.

Not all values can be set when using the ISP.

30

ISP_IO_COND_EN

When at 1, tells the boot process to use the ISP configuration in the flash User page to determine the I/O conditions to test to know which of the USB DFU ISP and the application to start.

31

ISP_FORCE

When at 1, tells the boot process to start the USB DFU ISP without testing any other condition.

 

AT32UC3A and AT32UC3B devices are shipped with the general-purpose fuses set to FC07FFFFh

 

For more information please refer to AVR32 UC3 USB DFU Bootloader